We propose a randomized, controlled clinical trial designed to assess long-term effects of a strict lifestyle-change program on lipids, blood pressure, myocardial perfusion, and coronary atherosclerosis. Fifty patients are randomly assigned to receive either lifestyle-change program plus usual medical care or to receive only usual medical care. Endpoint measures include lipids, lipoproteins, apoproteins, blood pressure reactivity, quantitative coronary arteriography, and cardiac positron emission tomography (PET) at baseline, after one year. In the experimental group, dietary cholesterol has decreased from 215.0 to 2.6 mg/day and total dietary fat has decreased from 70.0 to 15.0 grams/day, whereas dietary changes in the control group have been substantially less. In the experimental group after one year, total serum cholesterol decreased from 227 to 136 mg/d1, LDL decreased from 146 to 56 mg/d1, and HDL decreased from 39 to 35 mg/d1. Serum lipids in the control group decreased slightly but not significantly. After one year, in the experimental group there was a percent diameter stenosis regression, whereas in the control group there was a 5.69 percent diameter stenosis progression (p=0.025). Six of the first seven experimental patients demonstrated some overall regression of coronary atherosclerosis, whereas eight of the first ten control patients demonstrated some overall progression of coronary atherosclerosis. In the experimental group there was a 0.27 increase in coronary flow reserve (CFR), whereas the control group showed a 0.43 decrease in CFR (p=0.025). We propose to study these changes after four years to determine if patient in the experimental group can be motivated to maintain long-term adherence to this lifestyle-change program and to determine if the small degree of atherosclerosis regression detected after one year will continue to increase. Also, we propose to further develop and validate cardiac PET by comparing it to quantitative coronary arteriography and to develop statistical methods appropriate for the analyses of distribution- free randomized cluster experiments. If validated, PET would provide a noninvasive means of following regression/progression of CAD. The blinded arteriographic analysis and PET studies are carried out at UT with budget for this component of project submitted directly to NIH for direct funding to UT.